[02trailblazin]

i have a 94 grand cherokee with the 5.2. last weekend it would not start back up after wheelin it all day but would start back up the next day and run fine. this weekend it ran fine on sat. on sun it would start up but shut off after wheelin it for only a little bit and not want to restart. it would shut off like it had no fuel but the tank was full. once in awhile trying to restart it it would backfire. when it did restart i would have to keep the rpms up for it to keep runnin. now it will just crank and crank but wont start. what do i check?

 

[ajmorell]

Start by checking to see if you are getting fuel and spark when you're cranking.

 

[JeepInABox]

x2 since your fuel pump may be getting warm while its running and then the windings are opening up. when it cools off the windings touch and your back on the road.

 

[Psychdork]

Check for fuel and spark. You could pull one of the plugs and see if it is wet after cranking. Is the CEL on? Could scan it and see what it says. Could also be bad plug wires or coil wire. They act like this. I am wondering if wheeling it is related or just coincidental(possible moisture issue??). Let us know what you come up with.

 

[02trailblazin]

it has fuel up to the rails.i just put a new ignitoion coil on it to see if that was it and it still does it. i just put a new cap,plugs and wires on it a couple months ago but yea they could of got wet or somethin and messing up. i will take a plug out and make sure im gettin spark. thanks guys

 

[87mopar]

is your pump providing enough pressure? it may be running but not providing enough fuel. check the pressure

 

[02trailblazin]

i checked the pressure last week and it was reading right around 35. im thinkin it could be a spark issue.

 

[ajmorell]

Good plan on checking the plugs to see if they're wet with fuel. If they are NOT and you are NOT getting spark that would point to the ASD relay IMO. Possibly a loose ground or poor connection somewhere.

 

[JeepInABox]

35 psi when it would not start? did you check flow (trickle or stream) and did you have spark

 

[02trailblazin]

i checked the pressure last week when it was running. it just quit running this weekend. i have not checked the spark at the plugs yet. will do here in a little bit.

 

[JeepInABox]

Check the fuel pressure and flow again when it will not start.

 

[02trailblazin]

will do

 

[02trailblazin]

well i went and checked the plugs. they are not wet with fuel and are not getting any spark. what do i check next? would this be the crank postion sensor?

 

[ajmorell]

IIRC the crank sensor will only prevent spark but not fuel, but I might not be right on that. I know for a 100% fact that if something is tripping the ASD (Automatic shutdown) relay you won't get fuel or spark. I'd start by looking there. You can swap the A/C relay out for the ASD one to see if it is the relay itself. Otherwise check for places where the grounds could be shorted.

 

[JeepInABox]

The crank sensor tells the pcm to turn on the asd.
Sounds like a crank sensor or bad wire.

 

[02trailblazin]

we checked the asd relay and the power going to it. everything seemed good. so thats y we r goin for the crank sensor

 

[JeepInABox]

asd is powerd on for 5 seconds at ignition on then turns off untill it see's a rotating engine single from the crank sensor. asd powers fuel pump, injectors, coil pack... is the asd powered up while cranking?

 

[02trailblazin]

so i got the sensor in and now the jeep starts but backfires and acts like its starving for fuel. what to check next?

 

[JeepInABox]

have you cleaned the throttle and iac?

 

[02trailblazin]

no i havint cleaned the throttle yet. what is the iac?